Gatti Anthony A, Keir Peter J, Noseworthy Michael D, Beauchamp Marla K, Maly Monica R
School of Rehabilitation Sciences, McMaster University, Hamilton, Canada.
Department of Kinesiology, McMaster University, Hamilton, Canada.
Eur J Sport Sci. 2022 Mar;22(3):344-353. doi: 10.1080/17461391.2021.1902570. Epub 2021 Apr 2.
Overuse knee injuries are common in bicycling and are often attributed to poor bicycle-fit. Bicycle-fit for knee health focuses on setting saddle height to elicit a minimum knee flexion angle of 25-40°. Equations to predict saddle height include a single input, resulting in a likely suboptimal bicycle-fit. The purpose of this work was to develop an equation to predict saddle height from anthropometrics, bicycle geometry, and user-defined joint kinematics. Forty healthy adults (17 women, 23 men; mean (SD): 28.6 (7.2) years; 24.2 (2.6) kg/m) participated. Kinematic analyses were conducted for 18 three-minute bicycling bouts including all combinations of 3 horizontal and 3 vertical saddle positions, and 2 crank arm lengths. For both minimum and maximum knee flexion, predictors were identified using Least Absolute Shrinkage and Selection Operator (LASSO) regression, and final models were fit using linear regression. Secondary analyses determined if saddle height equations were sex dependent. The equation to predict saddle position from minimum knee flexion angle (R=0.97; root mean squared error (RMSE) = 1.15 cm) was: Saddle height (cm) = 7.41 + 0.82(inseam cm) - 0.1(minimum knee flexion °) + 0.003(inseam cm)(seat tube angle °). The maximum knee flexion equation (R=0.97; RMSE=1.15 cm) was: Saddle height (cm) = 41.63 + 0.78(inseam cm) - 0.25(maximum knee flexion °) + 0.002(inseam cm)(seat tube angle °). The saddle height equations were not dependent on sex. These equations provide a novel, practical strategy for bicycle-fit that accounts for rider anthropometrics, bicycle geometry and user-defined kinematics. This work developed simple equations to prescribed bicycle saddle height that elicits desired knee kinematics.Separate equations are presented for prescribing minimum or maximum knee flexion angle.Equations can be generalized to riders of both sexes, and a breadth of anthropometrics and ages.
过度使用导致的膝盖损伤在骑自行车时很常见，通常归因于自行车调校不当。为保护膝盖健康而进行的自行车调校着重于设定鞍座高度，以使膝盖的最小屈曲角度达到25至40°。预测鞍座高度的公式仅包含单一输入参数，这可能导致自行车调校效果欠佳。本研究旨在根据人体测量学、自行车几何结构和用户定义的关节运动学来开发一个预测鞍座高度的公式。40名健康成年人（17名女性，23名男性；平均（标准差）：28.6（7.2）岁；体重指数为24.2（2.6）kg/m²）参与了研究。对18次三分钟的骑行进行了运动学分析，包括3个水平鞍座位置、3个垂直鞍座位置以及2种曲柄长度的所有组合。对于最小和最大膝盖屈曲角度，使用最小绝对收缩和选择算子（LASSO）回归确定预测因子，并使用线性回归拟合最终模型。二次分析确定了鞍座高度公式是否与性别有关。根据最小膝盖屈曲角度预测鞍座位置的公式（R = 0.97；均方根误差（RMSE）= 1.15厘米）为：鞍座高度（厘米）= 7.41 + 0.82（内腿长厘米） - 0.1（最小膝盖屈曲角度°）+ 0.003（内腿长厘米）（座管角度°）。根据最大膝盖屈曲角度预测鞍座位置的公式（R = 0.97；RMSE = 1.15厘米）为：鞍座高度（厘米）= 41.63 + 0.78（内腿长厘米） - 0.25（最大膝盖屈曲角度°）+ 0.002（内腿长厘米）（座管角度°）。鞍座高度公式与性别无关。这些公式为自行车调校提供了一种新颖、实用的策略，该策略考虑了骑行者的人体测量学、自行车几何结构和用户定义的运动学。本研究开发了简单的公式来规定自行车鞍座高度，以实现所需的膝盖运动学。针对规定最小或最大膝盖屈曲角度分别给出了公式。这些公式可推广到不同性别的骑行者，以及各种人体测量特征和年龄范围的人群。
